/*
 * Copyright 2019 Mahmoud Romeh
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.github.resilience4j.retry.configure;

import io.github.resilience4j.consumer.DefaultEventConsumerRegistry;
import io.github.resilience4j.consumer.EventConsumerRegistry;
import io.github.resilience4j.fallback.FallbackDecorators;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import io.github.resilience4j.retry.event.RetryEvent;
import io.github.resilience4j.utils.AspectJOnClasspathCondition;
import io.github.resilience4j.utils.ReactorOnClasspathCondition;
import io.github.resilience4j.utils.RxJava2OnClasspathCondition;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;

import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

/**
 * {@link Configuration
 * Configuration} for resilience4j-retry.
 */
@Configuration
public class RetryConfiguration {

	/**
	 * @param retryConfigurationProperties retryConfigurationProperties retry configuration spring properties
	 * @param retryEventConsumerRegistry   the event retry registry
	 * @return the retry definition registry
	 */
	@Bean
	public RetryRegistry retryRegistry(RetryConfigurationProperties retryConfigurationProperties, EventConsumerRegistry<RetryEvent> retryEventConsumerRegistry) {

		RetryRegistry retryRegistry = createRetryRegistry(retryConfigurationProperties);
		registerEventConsumer(retryRegistry, retryEventConsumerRegistry, retryConfigurationProperties);
		retryConfigurationProperties.getInstances().forEach((name, properties) -> retryRegistry.retry(name, retryConfigurationProperties.createRetryConfig(name)));
		return retryRegistry;
	}


	/**
	 * Initializes a retry registry.
	 *
	 * @param retryConfigurationProperties The retry configuration properties.
	 * @return a RetryRegistry
	 */
	private RetryRegistry createRetryRegistry(RetryConfigurationProperties retryConfigurationProperties) {
		Map<String, RetryConfig> configs = retryConfigurationProperties.getConfigs()
				.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey,
						entry -> retryConfigurationProperties.createRetryConfig(entry.getValue())));

		return RetryRegistry.of(configs);
	}

	/**
	 * Registers the post creation consumer function that registers the consumer events to the retries.
	 *
	 * @param retryRegistry         The retry registry.
	 * @param eventConsumerRegistry The event consumer registry.
	 */
	private void registerEventConsumer(RetryRegistry retryRegistry,
	                                   EventConsumerRegistry<RetryEvent> eventConsumerRegistry, RetryConfigurationProperties retryConfigurationProperties) {
		retryRegistry.getEventPublisher().onEntryAdded(event -> registerEventConsumer(eventConsumerRegistry, event.getAddedEntry(), retryConfigurationProperties));
	}

	private void registerEventConsumer(EventConsumerRegistry<RetryEvent> eventConsumerRegistry, Retry retry, RetryConfigurationProperties retryConfigurationProperties) {
		int eventConsumerBufferSize = Optional.ofNullable(retryConfigurationProperties.getBackendProperties(retry.getName()))
				.map(io.github.resilience4j.common.retry.configuration.RetryConfigurationProperties.InstanceProperties::getEventConsumerBufferSize)
				.orElse(100);
		retry.getEventPublisher().onEvent(eventConsumerRegistry.createEventConsumer(retry.getName(), eventConsumerBufferSize));
	}

	/**
	 * @param retryConfigurationProperties retry configuration spring properties
	 * @param retryRegistry                retry in memory registry
	 * @return the spring retry AOP aspect
	 */
	@Bean
	@Conditional(value = {AspectJOnClasspathCondition.class})
	public RetryAspect retryAspect(RetryConfigurationProperties retryConfigurationProperties,
								   RetryRegistry retryRegistry, @Autowired(required = false) List<RetryAspectExt> retryAspectExtList,
								   FallbackDecorators fallbackDecorators) {
		return new RetryAspect(retryConfigurationProperties, retryRegistry, retryAspectExtList, fallbackDecorators);
	}

	@Bean
	@Conditional(value = {RxJava2OnClasspathCondition.class, AspectJOnClasspathCondition.class})
	public RxJava2RetryAspectExt rxJava2RetryAspectExt() {
		return new RxJava2RetryAspectExt();
	}

	@Bean
	@Conditional(value = {ReactorOnClasspathCondition.class, AspectJOnClasspathCondition.class})
	public ReactorRetryAspectExt reactorRetryAspectExt() {
		return new ReactorRetryAspectExt();
	}

	/**
	 * The EventConsumerRegistry is used to manage EventConsumer instances.
	 * The EventConsumerRegistry is used by the Retry events monitor to show the latest RetryEvent events
	 * for each Retry instance.
	 *
	 * @return a default EventConsumerRegistry {@link DefaultEventConsumerRegistry}
	 */
	@Bean
	public EventConsumerRegistry<RetryEvent> retryEventConsumerRegistry() {
		return new DefaultEventConsumerRegistry<>();
	}

}
